Aim: There is a critical need for effective therapies that are immediately available to control the spread of COVID-19 disease. Material & methods: Gamunex®-C and Flebogamma® DIF (Grifols) intravenous immunoglobulin (IVIG) products were tested using ELISA techniques for antibodies against several antigens of human common betacoronaviruses that may crossreact with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. Results: Both IVIGs showed consistent reactivity to components of the tested viruses. Positive crossreactivity was seen in SARS-CoV, middle east respiratory syndrome-CoV and SARS-CoV-2. For SARS-CoV-2, positive reactivity was observed at IVIG concentrations ranging from 100 μg/ml with Gamunex-C to 1 mg/ml with Flebogamma 5% DIF. Conclusion: Gamunex-C and Flebogamma DIF contain antibodies reacting against SARS-CoV-2 antigens. Studies to confirm the utility of IVIG preparations for COVID-19 management may be warranted.

Background: There is a crucial need for effective therapies that are immediately available to counteract COVID-19 disease. Recently, ELISA binding cross-reactivity against components of human epidemic coronaviruses with currently available intravenous immunoglobulins (IVIG) Gamunex-C and Flebogamma DIF (5% and 10%) have been reported. In this study, the same products were tested for neutralization activity against SARS-CoV-2, SARS-CoV and MERS-CoV and their potential as an antiviral therapy. Methods: The neutralization capacity of six selected lots of IVIG was assessed against SARS-CoV-2 (two different isolates), SARS-CoV and MERS-CoV in cell cultures. Infectivity neutralization was measured by determining the percent reduction in plaque-forming units (PFU) and by cytopathic effects for two IVIG lots in one of the SARS-CoV-2 isolates. Neutralization was quantified using the plaque reduction neutralization test 50 (PRNT50) in the PFU assay and the half maximal inhibitory concentration (IC50) in the cytopathic/cytotoxic method (calculated as the minus log10 dilution which reduced the viral titer by 50%). Results: All IVIG preparations showed neutralization of both SARS-CoV-2 isolates, ranging from 79 to 89.5% with PRNT50 titers from 4.5 to >5 for the PFU method and ranging from 47.0%-64.7% with an IC50 ~1 for the cytopathic method. All IVIG lots produced neutralization of SARS-CoV ranging from 39.5 to 55.1 % and PRNT50 values ranging from 2.0 to 3.3. No IVIG preparation showed significant neutralizing activity against MERS-CoV. Conclusion: In cell culture neutralization assays, the tested IVIG products contain antibodies with significant cross-neutralization capacity against SARS-CoV-2 and SARS-CoV. However, no neutralization capacity was demonstrated against MERS-CoV. These preparations are currently available and may be immediately useful for COVID-19 management.

No abstract

Background: There is a critical need for effective therapies that are immediately available to control the spread of COVID-19 disease. In this study, we assessed currently marketed intravenous immunoglobulin (IVIG) products for antibodies against human common coronaviruses that may cross-react with the SARS-CoV-2 virus.Methods: Gamunex ® -C and Flebogamma ® DIF (Grifols) IVIG were tested against several betacoronaviruses antigens using ELISA techniques: HCoV (undetermined antigen), HCoV-HKU1 (N protein), SARS-CoV (culture lysate), MERS-CoV (N protein; S1 protein/RBD; S protein), and SARS-CoV-2 (S1 protein). Results: Both IVIG products showed consistent reactivity to components of the tested viruses. Positive cross-reactivity was seen in SARS-CoV, MERS-CoV, and SARS-CoV-2. For SARS-CoV-2, positive reactivity was observed at IVIG concentrations ranging from 100 µg/mL with Gamunex-C to 1 mg/mL with Flebogamma 5% DIF. Conclusion:Gamunex-C and Flebogamma DIF IVIG contain antibodies reacting against SARS-CoV-2 antigens. These preparations may be useful for immediate treatment of COVID-19 disease.

Although progressive COVID-19 vaccinations provide a significant reduction of infection rate in the short- to mid- term, effective COVID-19 treatments will continue to be an urgent need. Methods: We have functionally characterized the anti-SARS-CoV-2 hyperimmune immunoglobulin (hIG) prepared from human COVID-19 convalescent plasma. SARS-CoV-2 virus neutralization was evaluated by four different methodologies (plaque reduction, virus induced cytotoxicity, TCID50 reduction and immunofluorimetry-based methodology) performed at four different laboratories and using four geographically different SARS-CoV-2 isolates (one each from USA and Italy; two from Spain). Two of the isolates contained the D614G mutation. Neutralization capacity against the original Wuhan SARS-CoV-2 straom and variants (D614G mutant, B.1.1.7, P.1 and B.1.351 variants) was evaluated using a pseudovirus platform expressing the corresponding spike (S) protein. The capacity to induce antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP) was also evaluated. Results: All the SARS-CoV-2 isolates tested were effectively neutralized by hIG solutions. This was confirmed by all four methodologies showing potent neutralization capacity. Wild-type SARS-CoV-2 and variants were effectively neutralized as demonstrated using the pseudovirus platform. The hIG solutions had the capacity to induce ADCC and ADCP against SARS-CoV-2 N and S proteins but not the E protein. Under our experimental conditions, very low concentrations (25-100 μg IgG/mL) were required to induce both effects. Besides the S protein, we observed a clear and potent effect triggered by antibodies in the hIG solutions against the SARS-CoV-2 N protein. Conclusions: These results show that, beyond neutralization, other IgG Fc-dependent pathways may play a role in the protection from and/or resolution of SARS-CoV-2 infection when using hIG COVID-19 products. This could be especially relevant for the treatment of more neutralization resistant SARS-CoV-2 variants of concern.